Definition:

pheochromocytoma (FEE-oh-KROH-moh-sy-TOH-muh)

Tumor that forms in the center of the adrenal gland (gland located above the kidney) that causes it to make too much adrenaline. Pheochromocytomas are usually benign (not cancer) but can cause high blood pressure, pounding headaches, heart palpitations, flushing of the face, nausea, and vomiting.